1. Field of the Invention
Painting and/or coating of vertical surfaces, particularly fences and wall structures.
2. Background of the Prior Art
The painting or coating (e.g., with corrosion resistant coatings) has been accomplished mainly by manual labor with brushes or rollers, or by use of spray equipment. For large projects, the cost of manual labor usually is prohibitive, which discourages proper maintenance; spraying processes applicable to such purposes generally are wasteful of paint and pose problems and liability due to airborne scattering of paint. Other problems are that fences and walls to be painted often are ten to twelve feet or more in height, requiring a scaffold or other means to reach them effectively. In the case of security fencing, it is common to have several strands of barbed wire at the top, sometimes oriented at a 30.degree.-45.degree. angle to the vertical posts, and at a height of perhaps eight to twelve feet. Manually applying paint or corrosion-resistant coatings to fences or walls under such circumstances therefore becomes unweildy and uneconomical; in some cases these factors may indeed discourage proper maintenance.
Benzuly U.S. Pat. No. 2,489,445, issued Nov. 29, 1949, discloses a paint spraying apparatus which is supported by sections of track mounted on brackets which must be previously affixed to the top railing of a fence, and therefore inherently requires extensive time-consuming labor and preparation and after-removal.
Webb U.S. Pat. No. 3,257,989 of Jun. 28, 1966 similarly shows a spraying unit which travels on a separate trackwork hooked onto the fencing; it also incorporates booms which must be swung (manually) upwardly and downwardly in order to cover the entire fence area. No means are provided for painting slanted upper sections of barbed wire or the like.
Lamarque U.S. Pat. No. 3,532,070, issued Oct. 6, 1970, discloses opposed spray units mounted on the boom of a vehicle. The vertical and lateral positioning of the spraying assembly is dictated solely by the movement of the vehicle over the adjacent terrain and/or the careful attention of the machine operator to handling the steering and boom controls continuously.